I have a start problem!
The car is a 1991 Honda CRX Si (manual gearbox).
When I turn the key on the main relay “chatters’, (the engine light is on and the ECU led is lit), the fuel pump is running and I have spark. (apparently the injectors are also “chattering”) Car fires once and is unable to run. The next couple of attempts, merely turns the engine over. If I unplug the injectors the chatter stops. It also appears while the injectors are plugged in (key on) they all have current (while “chattering”).
I tried a different resistor pack (which also test out correctly) and a different ECU all to no avail. I tend to think it is the main relay.
I have disconnected all engine sensors and no effect on the chattering. (I have had the engine out and am now looking for the ground to the ECU. (but would this cause the main relay to chatter) (Oh, I did check out the main relay via the Honda manual and it seems to check out fine) (also the fuel pump seems to be ok)

 

Sounds like a loose ground.
Take careful look at the grounds on the thermostat housing.

 

Check the ecu fuse in the engine bay's fuse box. It's probably blown.

 

Ground is the easy fix (especially if its the old 14g wire ground), fuses next, relays after

 

Are you sure it's the main relay or the starter solenoid? Sounds like a weak battery or weak battery connection.

 

Everyone thank you for your input. I am apparently retarded (sorry not necessarily politically correct.

I HAD MISSED THE GROUND TO THE ECU (yes, the one going to the thermostat housing)

I would have sworn I would not have made that mistake 0ops.

Thank you again everyone!!!

 

Haha, glad you got it figured out.